Device for pumping a liquid in a liquid line

ABSTRACT

The invention relates to a device for pumping a liquid in a liquid line, in particular in a bottling system. The object of the invention is a device for pumping a liquid in a liquid line, the liquid-guiding areas of which device can be cleaned and/or disinfected without disassembling the piston assembly or performing any other interventions from the exterior. According to the invention, a device for pumping a liquid in a liquid line ( 1 ) comprises a pump element ( 2 ) and two valves ( 3, 4 ) which are disposed in the liquid line upstream of and downstream from the pump element, said pump element ( 2 ) comprising a pump piston ( 6 ) operating in a cylinder ( 5 ). The inventive device is characterized in that said pump element ( 2 ) comprises a closed chamber ( 7 ) having a constant volume of a secondary liquid on which the pump piston ( 6 ) acts. Also, the chamber ( 7 ) is connected to the liquid line ( 1 ) by means of an elastic liquid-impermeable element ( 8 ), which element can be deformed under the pressure exerted by the volume of the secondary liquid displaced by the pump piston ( 6 ).

The present invention relates to a device for pumping a liquid in a liquid line, particularly in a bottling facility for filling of bottles.

Pump devices for pumping a liquid within a liquid line can be designed, e.g., as piston pumps, membrane pumps (diaphragm pumps), eccentric screw pumps, or peristaltic pumps. For different applications, it is necessary to convey (pump) a precisely defined volume per work cycle. One such application is, e.g., filling of liquids into containers, e.g. in the beverage industry. Here, it is sought to fill a bottle with a precisely defined volume of a beverage. This can be accomplished in various ways, e.g. by measuring a volumetric flow or by measuring the filling height.

A reliable method which can be used in particular in volumetric filling is the use of a piston pump in which a piston executes strokes in a cylinder and displaces a defined volume of liquid with each stroke. Thus, during a first stroke movement of the piston, a defined volume can be conveyed into the piston through a feed line from a storage container. The feed line is then shut off by a shutoff valve, which may also be in the form of a check valve, so that no liquid can flow back into the storage container.

Then the liquid inside the cylinder is displaced from the cylinder in the opposite direction by a piston stroke and fed through a line to the container which is to be filled. Depending on the forming process (for the container) and the filling process, and depending on the filling material with which the container is to be filled, this can be carried out under different pressures. With this method, an already formed container can be filled, or a preform can be simultaneously formed and filled under high pressure.

A problem with the use of such piston pumps is the cleaning. In particular, bottling facilities for bottling beverages have stringent hygiene requirements. This includes regular cleaning and disinfection, which need to be carried out as quickly as possible in order to avoid undue periods of idleness of the affected machinery. In addition, intervention in a machine, e.g. by removal of parts for cleaning and disinfection, is undesirable and should be avoided to the extent possible, in order to prevent the contamination of the machinery by externally introduced microorganisms. The regions of the machine which serve to convey the filling material should be isolated from the surroundings to the extent possible, and should be cleaned without any opening.

For the cleaning and disinfecting of such machines, largely without dismantling, various methods have been developed for so-called CIP (cleaning in place), during which the components remain in place in their original locations.

However, it is difficult to clean and disinfect the piston and cylinder in a piston arrangement for pumping a liquid, in which case the piston has to be uninstalled, as a rule, in order to remove impurities located between the piston and the cylinder. In particular, in the case of a piston which has a seal with respect to the matching cylinder surface, impurities in the region of the seal cannot be satisfactorily removed without disassembly.

Accordingly, it is an object of the present invention to devise a device for pumping a liquid in a liquid line wherein the regions of the device which guide the liquid can be cleaned and/or disinfected without disassembling the piston assembly or performing any other interventions from the exterior.

According to the invention, a device is proposed for pumping a liquid in a liquid line, in particular in a bottle filling line, which device is comprised of a pump element and two valves which are disposed in the liquid line upstream and downstream of the pump element, which pump element is comprised of a pump piston operating in a cylinder. The inventive device is characterized in that the pump element has a closed chamber with a constant volume of a secondary liquid, on which liquid the pump piston acts. The chamber is connected to the liquid line by an elastic, liquid-impermeable element which can be deformed under the pressure exerted by the volume of the secondary liquid displaced by the pumping piston.

Liquid located in the liquid line can be pumped by means of the inventive device, by movement of the piston. The volume delivered per working cycle is determined by the operating stroke distance of the piston and the diameter of the cylinder. By virtue of the fact that the piston operates only in the secondary liquid and does not come into contact with the liquid conveyed, the pumping device can be used for applications in which the liquid-guiding areas must be regularly cleaned. It is unnecessary for the piston pump to be disassembled for the cleaning. Cleaning-in-place methods can be used. The inventive device thus combines the advantage of easy cleanability of, e.g., membrane pumps, with the advantage of an easy to determine delivery volume of piston pumps.

The elastic element may be in the form of a bellows or an elastic membrane. Also, a roll membrane (roll-type diaphragm) or a roll bellows may be employed.

The secondary liquid may be, e.g., water or oil.

One or both of the valves in the liquid line may be check valves.

For the cleaning and/or disinfection, customary cleaning and/or disinfecting agents may be employed, which are introduced through the liquid line; such agents may be, in particular liquid or gaseous cleaning agents, e.g. steam.

The inventive method may be used for filling of already formed containers, or for simultaneous filling and forming of containers from preforms. The required pressure can be easily adjusted via the force applied to the piston.

Various exemplary embodiments of the invention are described in more detail below with reference to the accompanying drawings.

FIG. 1 shows schematically an embodiment of a pumping device according to the invention, with a bellows; and

FIGS. 2a and 2b show schematically a further embodiment of a pumping device according to the invention, with a membrane.

It is self-evident to a person skilled in the art that the drawings presented here are merely intended to illustrate the principle of the invention and are only schematic in nature and are not to scale. In particular, the illustrated dimensions are for illustrative purposes only. The actual dimensions and size ratios can be readily determined by a person skilled in the art on the basis of his/her technical knowledge.

FIG. 1 shows schematically an exemplary embodiment of a pump device according to the invention. The device serves to pump a liquid which is located in a liquid line 1, e.g. a liquid of a type typically present in a line in a bottling facility. In this application, a liquid to be bottled is to be conveyed from a storage container (not shown in the Figure), with the direction of conveyance indicated by the arrow V, wherewith in each case a defined volume of the liquid is introduced into a container (not shown), which liquid is conveyed in the direction of the arrow B.

The pumping device has a pump element 2 which is disposed in the liquid line 1 between two valves 3, 4, which here are in the form of check valves. The valve 3 is disposed upstream of the pump element 2 and the valve 4 is disposed downstream of the pump element 2.

The pump element 2 has a pump piston 6 operating in a cylinder 5. The pump element 2 also has a closed chamber 7 which contains a constant volume of water as a secondary liquid, which water is enclosed in the chamber 7. The pump piston 6 acts on the enclosed water volume.

The chamber 7 also has an elastic, liquid-impermeable bellows 8 a which is connected to the liquid line 1.

If (when) the pump piston 6 displaces liquid in the chamber 7, the elastic bellows 8 a is deformed, and transfers the pressure to the liquid in the liquid line 1, wherewith the volume displaced by the bellows 8 a in the liquid line 1 corresponds to the volume displaced by the pump piston 6. Thus, the volumetric control of the liquid delivered by the device corresponds to that of a piston pump.

At the same time, the filling-material-carrying regions of the device can be cleaned and/or disinfected without problems using CIP cleaning methods, without the need for disassembly. The bellows 8 a can be completely charged with a cleaning and/or disinfecting medium, and subjected to force from said medium, from the liquid line 1.

FIG. 2a shows a further exemplary embodiment of the pump device according to the invention. In contrast to the exemplary embodiment shown in FIG. 1, a membrane 8 b is used here as the elastic, liquid-impermeable element.

FIG. 2b shows how the membrane 8 b displaces liquid in the liquid line 1 when the piston 6 displaces the secondary liquid in the chamber 7. The volume displaced in the liquid line 1 (shown as crosshatched) exactly corresponds to the volume displaced by the piston 6 (also shown as crosshatched).

With this device, all of the regions which serve to guide the filling liquid can be cleaned and/or disinfected without disassembly. The device combines the advantages of piston pumps with the advantages of membrane pumps. 

1. A device for pumping a liquid in a liquid line comprising: a pump element comprising a pump piston operating in a cylinder; and two valves which are disposed in the liquid line upstream of and downstream from the pump element respectively; wherein said pump element comprises a closed chamber having a constant volume of a secondary liquid on which the pump piston acts; and wherein the chamber is connected to the liquid line by an elastic liquid-impermeable element, which element is deformable under pressure exerted by the volume of the secondary liquid displaced by the pump piston.
 2. The device according to claim 1, wherein the elastic element is a membrane or a roll membrane.
 3. The device according to claim 1, wherein the elastic element is a bellows or a roll bellows.
 4. The device according to claim 1, wherein the secondary liquid is water or oil.
 5. The device according to claim 1, wherein one or both of the valves are check valves. 